Lamellar changes in the keratoconic cornea.

Purpose: The purpose of this study was to identify ultrastructural changes associated with ectasia and to determine the association between lamellar count and corneal thinning.

Methods: Five surgically removed keratoconic corneal buttons and four, non-keratoconic, normal eye bank control corneas were processed for transmission electron microscopy using an established protocol, ensuring minimal tissue distortion. A sequence of overlapping digital images, spanning the full apical cone corneal thickness, was assembled.

Recurrence or re-emergence of keratoconus--what is the evidence telling us? Literature review and two case reports.

Keratoconus may recur following penetrating or lamellar keratoplasty, but latency is considerably longer in the former. Since keratoplasty involves only partial excision of the cornea, and recent research strongly indicates the presence of the pathology in the peripheral host cornea, the reappearance of the pathology after a latency period is most likely due to migration of the disease from host to donor cornea. This notion is further corroborated by the shorter latency period in partial thickness keratoplasty, where more of the diseased host cornea remains in place.

Quantified histopathology of the keratoconic cornea.

Purpose: This study systematically investigated and quantified histopathological changes in a series of keratoconic (Kc) corneas using a physiologically formulated fixative to not further distort the already distorted diseased corneas.

Methods: Twelve surgically removed Kc corneal buttons were immediately preserved and processed for light and transmission electron microscopy using an established corneal protocol. Measurements were taken from the central cone and peripheral regions of the host button.